US20140044283A1 - Amplification System, Carrier Tracking Systems and Related Methods for use in Parametric Sound Systems - Google Patents

Amplification System, Carrier Tracking Systems and Related Methods for use in Parametric Sound Systems Download PDF

Info

Publication number
US20140044283A1
US20140044283A1 US13/738,887 US201313738887A US2014044283A1 US 20140044283 A1 US20140044283 A1 US 20140044283A1 US 201313738887 A US201313738887 A US 201313738887A US 2014044283 A1 US2014044283 A1 US 2014044283A1
Authority
US
United States
Prior art keywords
signal
voltage
modulated carrier
carrier signal
processing system
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
US13/738,887
Other versions
US9036831B2 (en
Inventor
Elwood G. Norris
John Bryan Bolton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Turtle Beach Corp
Original Assignee
Parametric Sound Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US13/738,887 priority Critical patent/US9036831B2/en
Application filed by Parametric Sound Corp filed Critical Parametric Sound Corp
Assigned to PARAMETRIC SOUND CORPORATION reassignment PARAMETRIC SOUND CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NORRIS, ELWOOD G.
Publication of US20140044283A1 publication Critical patent/US20140044283A1/en
Assigned to BANK OF AMERICA, N.A., AS AGENT reassignment BANK OF AMERICA, N.A., AS AGENT MEMORANDUM AND NOTICE OF SECURITY INTEREST IN INTELLECTUAL PROPERTY Assignors: PARAMETRIC SOUND CORPORATION
Assigned to TURTLE BEACH CORPORATION reassignment TURTLE BEACH CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: PARAMETRIC SOUND CORPORATION
Publication of US9036831B2 publication Critical patent/US9036831B2/en
Application granted granted Critical
Assigned to CRYSTAL FINANCIAL LLC, AS AGENT reassignment CRYSTAL FINANCIAL LLC, AS AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TURTLE BEACH CORPORATION
Assigned to BANK OF AMERICA, N.A., AS AGENT reassignment BANK OF AMERICA, N.A., AS AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TURTLE BEACH CORPORATION, VOYETRA TURTLE BEACH, INC.
Assigned to CRYSTAL FINANCIAL LLC, AS AGENT reassignment CRYSTAL FINANCIAL LLC, AS AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TURTLE BEACH CORPORATION
Assigned to BANK OF AMERICA, N.A., AS AGENT reassignment BANK OF AMERICA, N.A., AS AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TURTLE BEACH CORPORATION, VOYETRA TURTLE BEACH, INC.
Assigned to TURTLE BEACH CORPORATION reassignment TURTLE BEACH CORPORATION TERMINATION AND RELEASE OF INTELLECTUAL PROPERTY SECURITY AGREEMENTS Assignors: CRYSTAL FINANCIAL LLC
Assigned to TURTLE BEACH CORPORATION reassignment TURTLE BEACH CORPORATION TERMINATION AND RELEASE OF INTELLECTUAL PROPERTY SECURITY AGREEMENTS Assignors: CRYSTAL FINANCIAL LLC
Assigned to BLUE TORCH FINANCE LLC, AS THE COLLATERAL AGENT reassignment BLUE TORCH FINANCE LLC, AS THE COLLATERAL AGENT SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: PERFORMANCE DESIGNED PRODUCTS LLC, TURTLE BEACH CORPORATION, VOYETRA TURTLE BEACH, INC.
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G5/00—Tone control or bandwidth control in amplifiers
    • H03G5/16—Automatic control
    • H03G5/165—Equalizers; Volume or gain control in limited frequency bands
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B11/00—Transmission systems employing sonic, ultrasonic or infrasonic waves
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2217/00—Details of magnetostrictive, piezoelectric, or electrostrictive transducers covered by H04R15/00 or H04R17/00 but not provided for in any of their subgroups
    • H04R2217/03—Parametric transducers where sound is generated or captured by the acoustic demodulation of amplitude modulated ultrasonic waves

Definitions

  • the present invention relates generally to the field of signal processing systems for use in parametric sound reproduction.
  • a parametric array in air results from the introduction of sufficiently intense, audio modulated ultrasonic signals into an air column.
  • Self demodulation, or down-conversion occurs along the air column resulting in an audible acoustic signal.
  • This process occurs because of the known physical principle that when two sound waves with different frequencies are radiated simultaneously in the same medium, a modulated waveform including the sum and difference of the two frequencies is produced by the non-linear interaction (parametric interaction) of the two sound waves.
  • the two original sound waves are ultrasonic waves and the difference between them is selected to be an audio frequency, an audible sound is generated by the parametric interaction.
  • Certain specific problems continue to arise when the emitter at issue utilizes a PVDF film.
  • Such films typically stretch or contract in reaction to changing environmental conditions such as heat, humidity, etc. (either solely as a result of exterior, environmental conditions, or as a result of operation of the emitter, or both).
  • This geometric change in the emitter film can result in poor performance of the emitter, or can result in damage being done to the film (and/or other components of the emitter).
  • a signal processing system for generating an ultrasonic signal from an audio signal including a compressor, operable to compress the audio signal, and an equalization circuit, operable to equalize the audio signal.
  • a modulation circuit is operable to combine the audio signal with a carrier signal to produce at least one modulated carrier signal.
  • a voltage detection and control circuit is operable to: detect a voltage of the modulated carrier signal; compare the detected voltage of the modulated carrier signal to a desired reference voltage; and cause the voltage of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired reference voltage.
  • a signal processing system for generating an ultrasonic signal from an audio signal including a compressor, operable to compress the audio signal, and an equalization circuit, operable to equalize the audio signal.
  • a modulation circuit is operable to combine the audio signal with a carrier signal to produce at least one modulated carrier signal.
  • a voltage detection and control circuit is operable to: detect a voltage of the modulated carrier signal; compare the detected voltage of the modulated carrier signal to a desired reference voltage; cause the frequency of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
  • a method of processing an audio signal to be provided to an ultrasonic emitter including: compressing an audio signal; equalizing the audio signal; combining the audio signal with a carrier signal to produce at least one modulated carrier signal; detecting a voltage of the modulated carrier signal; comparing the detected voltage of the modulated carrier signal to a desired voltage; and causing the voltage of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
  • a method of processing an audio signal to be provided to an ultrasonic emitter including: compressing an audio signal; equalizing the audio signal; combining the audio signal with a carrier signal to produce at least one modulated carrier signal; detecting a voltage of the modulated carrier signal; comparing the detected voltage of the modulated carrier signal to a desired voltage; and causing the frequency of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
  • FIG. 1 is a schematic diagram of an exemplary signal processing system in accordance with one embodiment of the invention.
  • FIG. 2 is a block diagram of an exemplary method in accordance with an embodiment of the invention.
  • the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result.
  • an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed.
  • the exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained.
  • the use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. In other words, a composition that is “substantially free of” an ingredient or element may still actually contain such item as long as there is no measurable effect thereof.
  • the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint.
  • Numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited.
  • a numerical range of “about 1 to about 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range.
  • included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually.
  • the present invention relates to improved signal processing systems for use in generating parametric audio signals.
  • FIG. 1 is provided as one exemplary manner in which the present invention can be carried out.
  • an amplifying system is provided that can utilize a Hilbert transform to generate a Single Side Band (“SSB”) carrier frequency.
  • SSB Single Side Band
  • an input audio signal is first processed using compression, equalization and distortion compensation. It is then modulated (or “mixed”) with a carrier signal at an exemplary carrier frequency of 44.1 kHz (or another suitable ultrasonic frequency) to form a single sideband signal for transmission into the air.
  • SSB Single Side Band
  • analog audio 100 can enter an analog gain 102 .
  • Analog gain control can modify the audio signal level before the signal is run through the Analog to Digital Converter (“ADC”) 104 .
  • Band pass filtering at 106 of the digital signal can be used to remove the highs and lows that are not of interest.
  • the digital signal can then be passed to the Digital Signal Processor (“DSP”) 108 .
  • DSP Digital Signal Processor
  • the signal can be amplitude compressed by compressor 110 to decrease the dynamic range. This can be advantageous in that the audio can have a very high dynamic range, and if not compressed, it can overflow the digital stages to follow.
  • Equalizer 112 can equalize the signal.
  • the next stage is the N th order distortion compensator 116 . While not so limited, in one aspect of the invention the order is “2” (that is, the signal is passed through the distortion compensator twice). In other embodiments, however, more (or fewer) passes may be made.
  • U.S. patents provide a good background discussion of the general workings of distortion compensators that can be used in the present system: U.S. Pat. Nos.
  • the distortion compensator 116 can compensate for the nonlinearities of the air column (acoustic channel) into which the emitter eventually emits the modulated wave.
  • the processed digital audio signal can be mixed with the SSB carrier at modulator 114 .
  • the modulated data can be band pass filtered at 118 , then run through the emitter correction at 120 . This can correct for any distortion of the ultrasound caused by the emitter.
  • the digital data can be passed to a DAC 122 for conversion back to analog.
  • Gain can be added at 124 to adjust the analog signal to the level best suited to the class D amplifier 126 . Gain can also be added or taken away at any point in the path (e.g., at the ADC, DSP and/or DAC).
  • a process that can be termed “Voltage Amplitude Tracking” can be utilized to optimize the performance of an emitter 128 , and to protect the emitter from becoming damaged.
  • One of the characteristics of typical emitter film is that it “warms up” while playing.
  • the emitter is typically comprised of a step up transformer and the film (which is a capacitor). The combination of these two forms a resonant circuit. When the film “warms up,” this resonant circuit can change frequency. This different frequency can be experienced by the Class D amplifier 126 as a different load. The result of this is that the voltage on the emitter can increase, and it can eventually “run away” and burn up the emitter.
  • the present system can implement voltage tracking (a generic detecting and control circuit is shown schematically at 132 ) which monitors the output of the Class D amplifier.
  • the audio and carrier signal can then be converted to a DC level.
  • this signal can be fed back to the DSP 108 to adjust the amplitude of the signal out of the DAC 122 .
  • the present system can continually set and monitor the level of the signal entering the emitter.
  • the above-described voltage tracking system and process can be particularly advantageous when applied to a stereo system. As no two emitters are exactly the same, this process can be utilized to deliver an optimal signal to each of the emitters (e.g., balance the two emitters). In this manner, the same voltage can be delivered to each emitter, even if the two emitters differ slightly.
  • the detecting and control circuit 132 can be used to implement a frequency tracking system.
  • frequency tracking can be implemented utilizing substantially the same hardware as discussed above in relation to the voltage amplitude tracking regime, except that, rather than adjusting the amplitude of the signal, the frequency of the carrier can be adjusted. This can be beneficial because, as the tuned resonant circuit “warms up,” its peak frequency can shift.
  • the present system can adjust the carrier frequency to stay in the “sweet spot” of the upper side band.
  • the voltage and/or frequency tracking and control system outlined above can be carried out in a number of manners, using various known components. Suitable regimes for doing so will be readily appreciated by one of ordinary skill in the art having possession of this disclosure.
  • a carrier drop and carrier mute regime can be implemented with the present system.
  • the carrier drop can be a technique by which the amplitude of the carrier is dropped if no audio is detected on the input.
  • There are several benefits to dropping the carrier including, without limitation, that carrier drop can reduce the power consumed but still maintain the emitter in a “warmed up” state in the case the audio returns.
  • the system can also include a carrier mute which completely cuts the carrier if the audio is not detected for an extended period of time.
  • the various components of the system described above and shown in the attached FIG. 1 can vary in position relative to one another (e.g., the signal sequence can vary from that shown), in some embodiments of the invention, the order of the components is precisely that as shown (e.g., the signal processing sequence is precisely that as shown). In other embodiments, the signal processing sequence can be only partially matched to that shown. In some embodiments, the signal processing sequence can be very important to producing clear audio output.
  • FIG. 2 illustrates on exemplary method in accordance with an embodiment of the invention.
  • This method can begin at 202 , where an audio signal (that is desired to be provided to an ultrasonic emitter) is compressed.
  • the audio signal can be equalized.
  • the audio signal can be combined with a carrier signal to produce at least one modulated carrier signal.
  • a voltage of the modulated carrier signal can be detected, and compared, at 210 , to a desired (or target, or reference) voltage.
  • the voltage or frequency of the modulated carrier signal can be adjusted. In this manner, the present technology can constantly maintain the modulated carrier signal at a target voltage or frequency. This can avoid, among other undesirable outcomes, having the signal “run away” and damage (e.g., overheat) the emitter.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Amplifiers (AREA)
  • Circuit For Audible Band Transducer (AREA)

Abstract

A signal processing system for generating an ultrasonic signal from an audio signal comprises a compressor, operable to compress the audio signal, and an equalization circuit, operable to equalize the audio signal. A modulation circuit is operable to combine the audio signal with a carrier signal to produce at least one modulated carrier signal. A voltage detection and control circuit is operable to: detect a voltage of the modulated carrier signal; compare the detected voltage of the modulated carrier signal to a desired voltage; and cause the voltage of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.

Description

    RELATED APPLICATIONS
  • Priority is claimed of U.S. Provisional Patent Application Ser. No. 61/585,112, filed Jan. 10, 2012, which is hereby incorporated herein by reference in its entirety.
    • BACKGROUND OF THE INVENTION
  • 1. Field of the Invention
  • The present invention relates generally to the field of signal processing systems for use in parametric sound reproduction.
  • 2. Related Art
  • A parametric array in air results from the introduction of sufficiently intense, audio modulated ultrasonic signals into an air column. Self demodulation, or down-conversion, occurs along the air column resulting in an audible acoustic signal. This process occurs because of the known physical principle that when two sound waves with different frequencies are radiated simultaneously in the same medium, a modulated waveform including the sum and difference of the two frequencies is produced by the non-linear interaction (parametric interaction) of the two sound waves. When the two original sound waves are ultrasonic waves and the difference between them is selected to be an audio frequency, an audible sound is generated by the parametric interaction.
  • While the theory of parametric sound production has been addressed in numerous publications, commercial attempts to capitalize on this intriguing phenomenon have largely failed. Most of these efforts have proved unsuccessful because many of the basic concepts integral to such technology while, relatively easy to produce and operate in laboratory conditions, have not scaled properly in applications where relatively high (or even useful) volume output is necessary. As these technologies have been scaled to commercial levels, distortion of parametrically produced sound output results in undesirable systems.
  • Certain specific problems continue to arise when the emitter at issue utilizes a PVDF film. Such films typically stretch or contract in reaction to changing environmental conditions such as heat, humidity, etc. (either solely as a result of exterior, environmental conditions, or as a result of operation of the emitter, or both). This geometric change in the emitter film can result in poor performance of the emitter, or can result in damage being done to the film (and/or other components of the emitter).
    • SUMMARY OF THE INVENTION
  • In accordance with one aspect of the invention, a signal processing system for generating an ultrasonic signal from an audio signal is provided, including a compressor, operable to compress the audio signal, and an equalization circuit, operable to equalize the audio signal. A modulation circuit is operable to combine the audio signal with a carrier signal to produce at least one modulated carrier signal. A voltage detection and control circuit is operable to: detect a voltage of the modulated carrier signal; compare the detected voltage of the modulated carrier signal to a desired reference voltage; and cause the voltage of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired reference voltage.
  • In accordance with another aspect of the invention, a signal processing system for generating an ultrasonic signal from an audio signal is provided, including a compressor, operable to compress the audio signal, and an equalization circuit, operable to equalize the audio signal. A modulation circuit is operable to combine the audio signal with a carrier signal to produce at least one modulated carrier signal. A voltage detection and control circuit is operable to: detect a voltage of the modulated carrier signal; compare the detected voltage of the modulated carrier signal to a desired reference voltage; cause the frequency of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
  • In accordance with another aspect of the invention, a method of processing an audio signal to be provided to an ultrasonic emitter is provided, including: compressing an audio signal; equalizing the audio signal; combining the audio signal with a carrier signal to produce at least one modulated carrier signal; detecting a voltage of the modulated carrier signal; comparing the detected voltage of the modulated carrier signal to a desired voltage; and causing the voltage of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
  • In accordance with another aspect of the invention, a method of processing an audio signal to be provided to an ultrasonic emitter is provided, including: compressing an audio signal; equalizing the audio signal; combining the audio signal with a carrier signal to produce at least one modulated carrier signal; detecting a voltage of the modulated carrier signal; comparing the detected voltage of the modulated carrier signal to a desired voltage; and causing the frequency of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • The following drawings illustrate exemplary embodiments for carrying out the invention. Like reference numerals refer to like parts in different views or embodiments of the present invention in the drawings.
  • FIG. 1 is a schematic diagram of an exemplary signal processing system in accordance with one embodiment of the invention; and
  • FIG. 2 is a block diagram of an exemplary method in accordance with an embodiment of the invention.
    •  DETAILED DESCRIPTION
  • Reference will now be made to the exemplary embodiments illustrated in the drawings, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Alterations and further modifications of the inventive features illustrated herein, and additional applications of the principles of the inventions as illustrated herein, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention.
    • DEFINITIONS
  • As used herein, the singular forms “a” and “the” can include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “an emitter” can include one or more of such emitters.
  • As used herein, the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result. For example, an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed. The exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained. The use of “substantially” is equally applicable when used in a negative connotation to refer to the complete or near complete lack of an action, characteristic, property, state, structure, item, or result. In other words, a composition that is “substantially free of” an ingredient or element may still actually contain such item as long as there is no measurable effect thereof.
  • As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be “a little above” or “a little below” the endpoint.
  • As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.
  • Numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. As an illustration, a numerical range of “about 1 to about 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4 and sub-ranges such as from 1-3, from 2-4, and from 3-5, etc., as well as 1, 2, 3, 4, and 5, individually.
  • This same principle applies to ranges reciting only one numerical value as a minimum or a maximum. Furthermore, such an interpretation should apply regardless of the breadth of the range or the characteristics being described.
  • Invention
  • The present invention relates to improved signal processing systems for use in generating parametric audio signals.
  • FIG. 1 is provided as one exemplary manner in which the present invention can be carried out. In accordance with one aspect of the invention, an amplifying system is provided that can utilize a Hilbert transform to generate a Single Side Band (“SSB”) carrier frequency. In the aspect shown, an input audio signal is first processed using compression, equalization and distortion compensation. It is then modulated (or “mixed”) with a carrier signal at an exemplary carrier frequency of 44.1 kHz (or another suitable ultrasonic frequency) to form a single sideband signal for transmission into the air.
  • In the exemplary embodiment shown, the audio processing can proceed as follows: analog audio 100 can enter an analog gain 102. Analog gain control can modify the audio signal level before the signal is run through the Analog to Digital Converter (“ADC”) 104. Band pass filtering at 106 of the digital signal can be used to remove the highs and lows that are not of interest. The digital signal can then be passed to the Digital Signal Processor (“DSP”) 108.
  • At the DSP 108, the signal can be amplitude compressed by compressor 110 to decrease the dynamic range. This can be advantageous in that the audio can have a very high dynamic range, and if not compressed, it can overflow the digital stages to follow. Equalizer 112 can equalize the signal. The next stage is the Nth order distortion compensator 116. While not so limited, in one aspect of the invention the order is “2” (that is, the signal is passed through the distortion compensator twice). In other embodiments, however, more (or fewer) passes may be made. The following U.S. patents provide a good background discussion of the general workings of distortion compensators that can be used in the present system: U.S. Pat. Nos. 6,584,205, 7,162,042, 7,729,498 and 7,596,229, which are each hereby incorporated herein by reference in their entirety. To the extent that any information in any of these four patents contradicts or teaches away from the present invention, that information is to be held subordinate to the present teachings.
  • The distortion compensator 116 can compensate for the nonlinearities of the air column (acoustic channel) into which the emitter eventually emits the modulated wave. After the distortion compensator, the processed digital audio signal can be mixed with the SSB carrier at modulator 114. The modulated data can be band pass filtered at 118, then run through the emitter correction at 120. This can correct for any distortion of the ultrasound caused by the emitter. Finally, the digital data can be passed to a DAC 122 for conversion back to analog. Gain can be added at 124 to adjust the analog signal to the level best suited to the class D amplifier 126. Gain can also be added or taken away at any point in the path (e.g., at the ADC, DSP and/or DAC).
  • In one aspect of the invention, a process that can be termed “Voltage Amplitude Tracking” can be utilized to optimize the performance of an emitter 128, and to protect the emitter from becoming damaged. One of the characteristics of typical emitter film is that it “warms up” while playing. The emitter is typically comprised of a step up transformer and the film (which is a capacitor). The combination of these two forms a resonant circuit. When the film “warms up,” this resonant circuit can change frequency. This different frequency can be experienced by the Class D amplifier 126 as a different load. The result of this is that the voltage on the emitter can increase, and it can eventually “run away” and burn up the emitter.
  • To address these issues, the present system can implement voltage tracking (a generic detecting and control circuit is shown schematically at 132) which monitors the output of the Class D amplifier. The audio and carrier signal can then be converted to a DC level. Using an ADC and a microcontroller, this signal can be fed back to the DSP 108 to adjust the amplitude of the signal out of the DAC 122. In this manner, the present system can continually set and monitor the level of the signal entering the emitter.
  • The above-described voltage tracking system and process can be particularly advantageous when applied to a stereo system. As no two emitters are exactly the same, this process can be utilized to deliver an optimal signal to each of the emitters (e.g., balance the two emitters). In this manner, the same voltage can be delivered to each emitter, even if the two emitters differ slightly.
  • In addition to, or instead of, the voltage amplitude tracking system and process outlined above, the detecting and control circuit 132 can be used to implement a frequency tracking system. In this aspect, frequency tracking can be implemented utilizing substantially the same hardware as discussed above in relation to the voltage amplitude tracking regime, except that, rather than adjusting the amplitude of the signal, the frequency of the carrier can be adjusted. This can be beneficial because, as the tuned resonant circuit “warms up,” its peak frequency can shift. The present system can adjust the carrier frequency to stay in the “sweet spot” of the upper side band.
  • The voltage and/or frequency tracking and control system outlined above can be carried out in a number of manners, using various known components. Suitable regimes for doing so will be readily appreciated by one of ordinary skill in the art having possession of this disclosure.
  • In one aspect of the invention, a carrier drop and carrier mute regime can be implemented with the present system. The carrier drop can be a technique by which the amplitude of the carrier is dropped if no audio is detected on the input. There are several benefits to dropping the carrier, including, without limitation, that carrier drop can reduce the power consumed but still maintain the emitter in a “warmed up” state in the case the audio returns. The system can also include a carrier mute which completely cuts the carrier if the audio is not detected for an extended period of time.
  • While the various components of the system described above and shown in the attached FIG. 1 can vary in position relative to one another (e.g., the signal sequence can vary from that shown), in some embodiments of the invention, the order of the components is precisely that as shown (e.g., the signal processing sequence is precisely that as shown). In other embodiments, the signal processing sequence can be only partially matched to that shown. In some embodiments, the signal processing sequence can be very important to producing clear audio output.
  • FIG. 2 illustrates on exemplary method in accordance with an embodiment of the invention. This method can begin at 202, where an audio signal (that is desired to be provided to an ultrasonic emitter) is compressed. At 204, the audio signal can be equalized. At 206, the audio signal can be combined with a carrier signal to produce at least one modulated carrier signal. At 208, a voltage of the modulated carrier signal can be detected, and compared, at 210, to a desired (or target, or reference) voltage. At 212, if the compared voltage differs by a predetermined amount from the desired voltage, the voltage or frequency of the modulated carrier signal can be adjusted. In this manner, the present technology can constantly maintain the modulated carrier signal at a target voltage or frequency. This can avoid, among other undesirable outcomes, having the signal “run away” and damage (e.g., overheat) the emitter.
  • It is to be understood that the above-referenced arrangements are illustrative of the application for the principles of the present invention. Numerous modifications and alternative arrangements can be devised without departing from the spirit and scope of the present invention while the present invention has been shown in the drawings and described above in connection with the exemplary embodiments(s) of the invention. It will be apparent to those of ordinary skill in the art that numerous modifications can be made without departing from the principles and concepts of the invention as set forth in the examples.

Claims (20)

What is claimed is:
1. A signal processing system for generating an ultrasonic signal from an audio signal, comprising:
a compressor, operable to compress the audio signal;
an equalization circuit, operable to equalize the audio signal;
a modulation circuit, operable to combine the audio signal with a carrier signal to produce at least one modulated carrier signal; and
a voltage detection and control circuit, operable to:
i) detect a voltage of the modulated carrier signal;
ii) compare the detected voltage of the modulated carrier signal to a desired voltage; and
iii) cause the voltage of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
2. The signal processing system of claim 1, wherein the compressor, the equalization circuit and the modulation circuit are portions of a digital signal processing (“DSP”) system, and wherein the digital signal processing system is at least partially controllable by the voltage detection and control circuit.
3. The signal processing system of claim 2, further comprising an analog-to-digital converter (“ADC”) that converts an analog input audio signal to a digital signal for processing by the digital signal processing system.
4. The signal processing system of claim 3, further comprising a band pass filter, operably disposed after the ADC.
5. The signal processing system of claim 1, further comprising a distortion compensator, operable to pre-compensate for acoustic distortion produced in an air column in which the audio signal is demodulated.
6. The signal processing system of claim 1, further comprising an emitter correction circuit, to prevent emitter distortion from degrading performance of the distortion compensator.
7. A signal processing system for generating an ultrasonic signal from an audio signal, comprising:
a compressor, operable to compress the audio signal;
an equalization circuit, operable to equalize the audio signal;
a modulation circuit, operable to combine the audio signal with a carrier signal to produce at least one modulated carrier signal; and
a frequency detection and control circuit, operable to:
i) detect a voltage of the modulated carrier signal;
ii) compare the detected voltage of the modulated carrier signal to a desired voltage; and
iii) cause the frequency of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
8. The signal processing system of claim 7, wherein the compressor, the equalization circuit and the modulation circuit are portions of a digital signal processing (“DSP”) system, and wherein the digital signal processing system is at least partially controllable by the frequency detection and control circuit.
9. The signal processing system of claim 8, further comprising an analog-to-digital converter (“ADC”) that converts an analog input audio signal to a digital signal for processing by the digital signal processing system.
10. The signal processing system of claim 9, further comprising a band pass filter, operably disposed after the ADC.
11. The signal processing system of claim 7, further comprising a distortion compensator, operable to pre-compensate for acoustic distortion produced in an air column in which the audio signal is demodulated.
12. The signal processing system of claim 7, further comprising an emitter correction circuit, to prevent emitter distortion from degrading performance of the distortion compensator.
13. A method of processing an audio signal to be provided to an ultrasonic emitter, the method comprising:
compressing an audio signal;
equalizing the audio signal;
combining the audio signal with a carrier signal to produce at least one modulated carrier signal;
detecting a voltage of the modulated carrier signal;
comparing the detected voltage of the modulated carrier signal to a desired voltage; and
causing the voltage of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
14. The method of claim 13, wherein compression, equalization and combining are performed by a digital signal processing (“DSP”) system, and wherein the digital signal processing system is at least partially controllable by a voltage detection and control circuit.
15. The method of claim 14, wherein adjusting the voltage of the modulated carrier signal is performed in response to a command from the voltage detection and control circuit.
16. The method of claim 14, wherein detecting the voltage of the modulated carrier signal is performed after the modulated carrier signal is converted to an analog signal.
17. A method of processing an audio signal to be provided to an ultrasonic emitter, the method comprising:
compressing an audio signal;
equalizing the audio signal;
combining the audio signal with a carrier signal to produce at least one modulated carrier signal;
detecting an average voltage amplitude of the modulated carrier signal;
comparing the detected average voltage amplitude of the modulated carrier signal to a desired reference voltage; and
causing the frequency of the modulated carrier signal to be adjusted if the compared voltage differs by a predetermined amount from the desired voltage.
18. The method of claim 17, wherein compression, equalization and combining are performed by a digital signal processing (“DSP”) system, and wherein the digital signal processing system is at least partially controllable by a voltage detection and control circuit.
19. The method of claim 18, wherein adjusting the frequency of the modulated carrier signal is performed in response to a command from the voltage detection and control circuit.
20. The method of claim 18, wherein detecting the voltage of the modulated carrier signal is performed after the modulated carrier signal is converted to an analog signal.
US13/738,887 2012-01-10 2013-01-10 Amplification system, carrier tracking systems and related methods for use in parametric sound systems Active 2033-10-15 US9036831B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US13/738,887 US9036831B2 (en) 2012-01-10 2013-01-10 Amplification system, carrier tracking systems and related methods for use in parametric sound systems

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201261585112P 2012-01-10 2012-01-10
US13/738,887 US9036831B2 (en) 2012-01-10 2013-01-10 Amplification system, carrier tracking systems and related methods for use in parametric sound systems

Publications (2)

Publication Number Publication Date
US20140044283A1 true US20140044283A1 (en) 2014-02-13
US9036831B2 US9036831B2 (en) 2015-05-19

Family

ID=48781911

Family Applications (1)

Application Number Title Priority Date Filing Date
US13/738,887 Active 2033-10-15 US9036831B2 (en) 2012-01-10 2013-01-10 Amplification system, carrier tracking systems and related methods for use in parametric sound systems

Country Status (2)

Country Link
US (1) US9036831B2 (en)
WO (1) WO2013106596A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140161278A1 (en) * 2011-09-22 2014-06-12 Panasonic Corporation Sound reproduction device
WO2015159037A1 (en) * 2014-04-18 2015-10-22 Akoustic Arts Unidirectional loudspeaker enclosure

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9332344B2 (en) 2013-06-13 2016-05-03 Turtle Beach Corporation Self-bias emitter circuit

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4546391A (en) * 1982-02-04 1985-10-08 Olympus Optical Co., Ltd. Video signal recording apparatus
US4613912A (en) * 1982-09-10 1986-09-23 Hitachi, Ltd. Recording and reproducing apparatus for a video tape recorder
US5539705A (en) * 1994-10-27 1996-07-23 Martin Marietta Energy Systems, Inc. Ultrasonic speech translator and communications system
US20040047477A1 (en) * 2001-07-11 2004-03-11 Bank Jeevan G. Power amplification for parametric loudspeaker
US20070127746A1 (en) * 2005-12-07 2007-06-07 Seiko Epson Corporation Drive control method of electrostatic-type ultrasonic transducer, electrostatic-type ultrasonic transducer, ultrasonic speaker using electrostatic-type ultrasonic transducer, audio signal reproducing method, superdirectional acoustic system, and display
US20080137881A1 (en) * 2006-02-07 2008-06-12 Anthony Bongiovi System and method for digital signal processing
US20080152172A1 (en) * 2006-12-20 2008-06-26 Seiko Epson Corporation Electrostatic ultrasonic transducer, and ultrasonic speaker, audio signal reproduction method, ultra-directive sound system, and display apparatus using electrostatic ultrasonic transducer
US20100260362A1 (en) * 2009-04-10 2010-10-14 Sander Wendell B Electronic device and external equipment with configurable audio path circuitry
US8849185B2 (en) * 2003-04-15 2014-09-30 Ipventure, Inc. Hybrid audio delivery system and method therefor

Family Cites Families (169)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1616639A (en) 1921-06-03 1927-02-08 Western Electric Co High-frequency sound-transmission system
US1764008A (en) 1928-10-24 1930-06-17 United Reproducers Patents Cor Push-pull electrostatic sound reproducer
NL29692C (en) 1929-04-30
US1809754A (en) 1929-05-13 1931-06-09 Joseph J Steedle Electrostatic reproducer
BE373730A (en) 1929-09-27
US1951669A (en) 1931-07-17 1934-03-20 Ramsey George Method and apparatus for producing sound
US2461344A (en) 1945-01-29 1949-02-08 Rca Corp Signal transmission and receiving apparatus
US2855467A (en) 1953-12-11 1958-10-07 Curry Electronics Inc Loud speakers
US3008013A (en) 1954-07-20 1961-11-07 Ferranti Ltd Electrostatic loudspeakers
BE540809A (en) 1954-08-26
US3012222A (en) 1957-08-08 1961-12-05 Hagemann Julius System for displaying sonic echoes from underwater targets
US2935575A (en) 1957-08-20 1960-05-03 Philco Corp Loud-speakers
US2975307A (en) 1958-01-02 1961-03-14 Ibm Capacitive prime mover
US2975243A (en) 1958-01-17 1961-03-14 Philco Corp Transducers
US3836951A (en) 1960-05-05 1974-09-17 Us Navy Heterodyne autocorrelation guidance system
NL281549A (en) 1961-09-25
US3345469A (en) 1964-03-02 1967-10-03 Rod Dev Corp Electrostatic loudspeakers
US3389226A (en) 1964-12-29 1968-06-18 Gen Electric Electrostatic loudspeaker
US3373251A (en) 1965-02-23 1968-03-12 Shure Bros Electrostatic transducer
US3710332A (en) 1966-04-21 1973-01-09 Federal Defense Minister Method and apparatus for finding the direction of signals
US3398810A (en) 1967-05-24 1968-08-27 William T. Clark Locally audible sound system
US3544733A (en) 1967-06-15 1970-12-01 Minnesota Mining & Mfg Electrostatic acoustic transducer
US3461421A (en) 1967-07-25 1969-08-12 Collins Radio Co Advanced direction finding sonobuoy system
US3654403A (en) 1969-05-01 1972-04-04 Chester C Pond Electrostatic speaker
US3612211A (en) 1969-07-02 1971-10-12 William T Clark Method of producing locally occurring infrasound
US3613069A (en) 1969-09-22 1971-10-12 Gen Dynamics Corp Sonar system
GB1357329A (en) 1970-06-23 1974-06-19 Nat Res Dev Detection apparatus
US3821490A (en) 1970-10-09 1974-06-28 Chester C Pond Electroacoustic transducer especially electrostatic speakers and systems
US3723957A (en) 1970-11-20 1973-03-27 M Damon Acoustic navigation system
US3674946A (en) 1970-12-23 1972-07-04 Magnepan Inc Electromagnetic transducer
FR2137567B1 (en) 1971-05-07 1977-08-26 Rank Organisation Ltd
US3787642A (en) 1971-09-27 1974-01-22 Gte Automatic Electric Lab Inc Electrostatic transducer having resilient electrode
US3816774A (en) 1972-01-28 1974-06-11 Victor Company Of Japan Curved piezoelectric elements
GB1428405A (en) 1972-05-26 1976-03-17 Rank Organisation Ltd Electro-acoustic transducers
JPS5223333Y2 (en) 1972-06-17 1977-05-27
US3892927A (en) 1973-09-04 1975-07-01 Theodore Lindenberg Full range electrostatic loudspeaker for audio frequencies
US3919499A (en) 1974-01-11 1975-11-11 Magnepan Inc Planar speaker
DE2461278B2 (en) 1974-12-23 1976-12-16 Foster Electric Co., Ltd., Tokio ELECTROACOUSTIC CONVERTER
GB1520118A (en) 1975-08-11 1978-08-02 Rank Organisation Ltd Transducers
US4056742A (en) 1976-04-30 1977-11-01 Tibbetts Industries, Inc. Transducer having piezoelectric film arranged with alternating curvatures
US4146847A (en) 1976-11-05 1979-03-27 Trio Kabushiki Kaisha Power limiting circuitry for use with power amplifier
GB1566616A (en) 1977-03-29 1980-05-08 Davall & Sons Ltd Navigational aids
FR2409654B1 (en) 1977-11-17 1985-10-04 Thomson Csf PIEZOELECTRIC TRANSDUCER DEVICE AND MANUFACTURING METHOD THEREOF
US4242541A (en) 1977-12-22 1980-12-30 Olympus Optical Co., Ltd. Composite type acoustic transducer
US4160882A (en) 1978-03-13 1979-07-10 Driver Michael L Double diaphragm electrostatic transducer each diaphragm comprising two plastic sheets having different charge carrying characteristics
US4322877A (en) 1978-09-20 1982-04-06 Minnesota Mining And Manufacturing Company Method of making piezoelectric polymeric acoustic transducer
US4210786A (en) 1979-01-24 1980-07-01 Magnepan, Incorporated Magnetic field structure for planar speaker
US4295214A (en) 1979-08-23 1981-10-13 Rockwell International Corporation Ultrasonic shear wave transducer
DE2950411C2 (en) 1979-12-14 1986-07-03 Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen Mbh, 8000 Muenchen Rectifier device with filtered output voltage
US4289936A (en) 1980-04-07 1981-09-15 Civitello John P Electrostatic transducers
US4314306A (en) 1980-07-14 1982-02-02 American Standard Inc. Signal-powered receiver
US4378596A (en) 1980-07-25 1983-03-29 Diasonics Cardio/Imaging, Inc. Multi-channel sonic receiver with combined time-gain control and heterodyne inputs
NL8004351A (en) 1980-07-30 1982-03-01 Philips Nv ELECTRIC CONVERTER.
US4245136A (en) 1980-08-08 1981-01-13 Krauel Jr Robert W Monitor ampliphones
US4385210A (en) 1980-09-19 1983-05-24 Electro-Magnetic Corporation Electro-acoustic planar transducer
US4418404A (en) 1981-10-01 1983-11-29 The United States Of America As Represented By The Secretary Of The Navy Single-sideband acoustic telemetry
US4429193A (en) 1981-11-20 1984-01-31 Bell Telephone Laboratories, Incorporated Electret transducer with variable effective air gap
US4439642A (en) 1981-12-28 1984-03-27 Polaroid Corporation High energy ultrasonic transducer
US4471172A (en) 1982-03-01 1984-09-11 Magnepan, Inc. Planar diaphragm transducer with improved magnetic circuit
US4480155A (en) 1982-03-01 1984-10-30 Magnepan, Inc. Diaphragm type magnetic transducer
AT379269B (en) 1982-05-13 1985-12-10 Philips Nv CIRCUIT ARRANGEMENT FOR GENERATING A CONTROL VOLTAGE FOR A PIEZOELECTRICAL ELEMENT OF A POSITIONING DEVICE
US4550228A (en) 1983-02-22 1985-10-29 Apogee Acoustics, Inc. Ribbon speaker system
US4558184A (en) 1983-02-24 1985-12-10 At&T Bell Laboratories Integrated capacitive transducer
DE3331727C2 (en) 1983-09-02 1995-06-08 Betr Forsch Inst Angew Forsch Electromagnetic transducer
US4888086A (en) 1983-09-15 1989-12-19 Ultrasonic Arrays, Inc. Ultrasonic method
US4887246A (en) 1983-09-15 1989-12-12 Ultrasonic Arrays, Inc. Ultrasonic apparatus, system and method
US4872148A (en) 1984-03-08 1989-10-03 Polaroid Corporation Ultrasonic transducer for use in a corrosive/abrasive environment
JPS60190100A (en) 1984-03-09 1985-09-27 Murata Mfg Co Ltd Piezoelectric speaker
DE3590430T1 (en) 1984-08-28 1986-09-18 Matsushita Electric Industrial Co., Ltd., Kadoma, Osaka Loudspeaker system with a pronounced directional effect
DE3501808A1 (en) 1985-01-21 1986-07-24 Siemens AG, 1000 Berlin und 8000 München ULTRASONIC CONVERTER
US4695986A (en) 1985-03-28 1987-09-22 Ultrasonic Arrays, Inc. Ultrasonic transducer component and process for making the same and assembly
US5054081B1 (en) 1985-04-02 1994-06-28 Roger A West Electrostatic transducer with improved bass response utilizing distributed bass resonance energy
US4673888A (en) 1986-09-02 1987-06-16 Electro-Voice, Inc. Power control system
US4716353A (en) 1986-09-02 1987-12-29 Electro-Voice Inc. Battery charger
US4751419A (en) 1986-12-10 1988-06-14 Nitto Incorporated Piezoelectric oscillation assembly including several individual piezoelectric oscillation devices having a common oscillation plate member
US4803733A (en) 1986-12-16 1989-02-07 Carver R W Loudspeaker diaphragm mounting system and method
GB8704314D0 (en) 1987-02-24 1987-04-01 Scient Generics Ltd Noise attenuation
US4837838A (en) 1987-03-30 1989-06-06 Eminent Technology, Inc. Electromagnetic transducer of improved efficiency
JPS63286145A (en) 1987-05-19 1988-11-22 Hitachi Ltd Talking apparatus of mr imaging apparatus
DE3731196A1 (en) 1987-09-17 1989-03-30 Messerschmitt Boelkow Blohm FREQUENCY SELECTIVE SOUND CONVERTER
NL8702589A (en) 1987-10-30 1989-05-16 Microtel Bv ELECTRO-ACOUSTIC TRANSDUCENT OF THE KIND OF ELECTRET, AND A METHOD FOR MANUFACTURING SUCH TRANSDUCER.
JPH02197183A (en) 1988-03-29 1990-08-03 Pennwalt Corp Laminated piezoelectric structure and its forming method
US4939784A (en) 1988-09-19 1990-07-03 Bruney Paul F Loudspeaker structure
JP2745147B2 (en) 1989-03-27 1998-04-28 三菱マテリアル 株式会社 Piezoelectric transducer
US4991148A (en) 1989-09-26 1991-02-05 Gilchrist Ian R Acoustic digitizing system
US5164991A (en) 1990-02-13 1992-11-17 Johnson Thomas J Variable input amplified speaker with improved power input section
EP0480097B1 (en) 1990-10-12 1994-12-21 Siemens Audiologische Technik GmbH Hearing-aid with data memory
US5361381A (en) 1990-10-23 1994-11-01 Bose Corporation Dynamic equalizing of powered loudspeaker systems
US5430805A (en) 1990-12-27 1995-07-04 Chain Reactions, Inc. Planar electromagnetic transducer
AU1189592A (en) 1991-01-17 1992-08-27 Roger A. Adelman Improved hearing apparatus
US5115672A (en) 1991-02-11 1992-05-26 Westinghouse Electric Corp. System and method for valve monitoring using pipe-mounted ultrasonic transducers
DE4200170C2 (en) 1992-01-07 1994-11-03 Rheinmetall Gmbh Method and acoustic sensor for determining the distance of a sound-producing target
US5287331A (en) 1992-10-26 1994-02-15 Queen's University Air coupled ultrasonic transducer
US5357578A (en) 1992-11-24 1994-10-18 Canon Kabushiki Kaisha Acoustic output device, and electronic apparatus using the acoustic output device
US5392358A (en) 1993-04-05 1995-02-21 Driver; Michael L. Electrolytic loudspeaker assembly
US5487114A (en) 1994-02-02 1996-01-23 Dinh; Khanh Magnetless speaker
US5684884A (en) 1994-05-31 1997-11-04 Hitachi Metals, Ltd. Piezoelectric loudspeaker and a method for manufacturing the same
US5638456A (en) 1994-07-06 1997-06-10 Noise Cancellation Technologies, Inc. Piezo speaker and installation method for laptop personal computer and other multimedia applications
FR2730853B1 (en) 1995-02-17 1997-04-30 Inst Franco Allemand De Rech D PROCESS FOR POLARIZING A SHEET OF LARGE SURFACE FERROELECTRIC MATERIAL
US5889870A (en) 1996-07-17 1999-03-30 American Technology Corporation Acoustic heterodyne device and method
US6108427A (en) 1996-07-17 2000-08-22 American Technology Corporation Method and apparatus for eliminating audio feedback
US6229899B1 (en) 1996-07-17 2001-05-08 American Technology Corporation Method and device for developing a virtual speaker distant from the sound source
US6011855A (en) 1997-03-17 2000-01-04 American Technology Corporation Piezoelectric film sonic emitter
US6188772B1 (en) 1998-01-07 2001-02-13 American Technology Corporation Electrostatic speaker with foam stator
US6151398A (en) 1998-01-13 2000-11-21 American Technology Corporation Magnetic film ultrasonic emitter
US6304662B1 (en) 1998-01-07 2001-10-16 American Technology Corporation Sonic emitter with foam stator
US5885129A (en) 1997-03-25 1999-03-23 American Technology Corporation Directable sound and light toy
US5859915A (en) 1997-04-30 1999-01-12 American Technology Corporation Lighted enhanced bullhorn
US6106399A (en) 1997-06-16 2000-08-22 Vr-1, Inc. Internet audio multi-user roleplaying game
IL121155A (en) 1997-06-24 2000-12-06 Be4 Ltd Headphone assembly and a method for simulating an artificial sound environment
US6023153A (en) 1997-09-23 2000-02-08 Crest Audio, Inc. Audio amplifier having power factor correction
JP3267231B2 (en) 1998-02-23 2002-03-18 日本電気株式会社 Super directional speaker
JP2000050387A (en) 1998-07-16 2000-02-18 Massachusetts Inst Of Technol <Mit> Parameteric audio system
US6775388B1 (en) 1998-07-16 2004-08-10 Massachusetts Institute Of Technology Ultrasonic transducers
US20050100181A1 (en) 1998-09-24 2005-05-12 Particle Measuring Systems, Inc. Parametric transducer having an emitter film
US6241612B1 (en) 1998-11-09 2001-06-05 Cirrus Logic, Inc. Voice communication during a multi-player game
US7391872B2 (en) 1999-04-27 2008-06-24 Frank Joseph Pompei Parametric audio system
EP1484944A3 (en) 1999-04-30 2004-12-15 Sennheiser electronic GmbH &amp; Co. KG Method for reproducing an audio signal with an ultrasonic loudspeaker
US6498531B1 (en) 2000-08-14 2002-12-24 Spectron Digital class-D audio amplifier
US7596229B2 (en) 1999-08-26 2009-09-29 American Technology Corporation Parametric audio system for operation in a saturated air medium
US6584205B1 (en) 1999-08-26 2003-06-24 American Technology Corporation Modulator processing for a parametric speaker system
US20050195985A1 (en) 1999-10-29 2005-09-08 American Technology Corporation Focused parametric array
US6628791B1 (en) 1999-10-29 2003-09-30 American Technology Corporation Signal derived bias supply for electrostatic loudspeakers
US7110951B1 (en) 2000-03-03 2006-09-19 Dorothy Lemelson, legal representative System and method for enhancing speech intelligibility for the hearing impaired
US6631196B1 (en) 2000-04-07 2003-10-07 Gn Resound North America Corporation Method and device for using an ultrasonic carrier to provide wide audio bandwidth transduction
US6914991B1 (en) 2000-04-17 2005-07-05 Frank Joseph Pompei Parametric audio amplifier system
US6411015B1 (en) 2000-05-09 2002-06-25 Measurement Specialties, Inc. Multiple piezoelectric transducer array
US7369665B1 (en) 2000-08-23 2008-05-06 Nintendo Co., Ltd. Method and apparatus for mixing sound signals
US6940468B2 (en) 2001-02-15 2005-09-06 Integral Technologies, Inc. Transformers or inductors (“transductors”) and antennas manufactured from conductive loaded resin-based materials
US20030091203A1 (en) 2001-08-31 2003-05-15 American Technology Corporation Dynamic carrier system for parametric arrays
EP1444861B1 (en) 2001-10-09 2020-03-18 Frank Joseph Pompei Ultrasonic transducer for parametric array
CA2474257A1 (en) 2002-01-18 2003-08-07 American Technology Corporation Modulator- amplifier
US7536008B2 (en) 2002-03-02 2009-05-19 Logitech Europe S.A. Antihelix-conforming ear-mount for personal audio-set
US20030215165A1 (en) 2002-05-20 2003-11-20 Hogan Robert E. Easy-open strip and bags incorporating the same
US20040052387A1 (en) 2002-07-02 2004-03-18 American Technology Corporation. Piezoelectric film emitter configuration
US7850526B2 (en) 2002-07-27 2010-12-14 Sony Computer Entertainment America Inc. System for tracking user manipulations within an environment
US20040114770A1 (en) 2002-10-30 2004-06-17 Pompei Frank Joseph Directed acoustic sound system
FR2852779B1 (en) 2003-03-20 2008-08-01 PROCESS FOR PROCESSING AN ELECTRICAL SIGNAL OF SOUND
US20040208324A1 (en) 2003-04-15 2004-10-21 Cheung Kwok Wai Method and apparatus for localized delivery of audio sound for enhanced privacy
US8323106B2 (en) 2008-05-30 2012-12-04 Sony Computer Entertainment America Llc Determination of controller three-dimensional location using image analysis and ultrasonic communication
WO2005036921A2 (en) 2003-10-08 2005-04-21 American Technology Corporation Parametric loudspeaker system for isolated listening
WO2005043771A1 (en) 2003-10-23 2005-05-12 American Technology Corporation Method of adusting linear parameters of a parametric ultrasonic signal to reduce non-linearities in decoupled audio output waves and system including same
SG115665A1 (en) 2004-04-06 2005-10-28 Sony Corp Method and apparatus to generate an audio beam with high quality
JP2005353989A (en) 2004-06-14 2005-12-22 Jfe Ferrite Corp Complex inductor
US7785197B2 (en) 2004-07-29 2010-08-31 Nintendo Co., Ltd. Voice-to-text chat conversion for remote video game play
US8565449B2 (en) 2006-02-07 2013-10-22 Bongiovi Acoustics Llc. System and method for digital signal processing
JP2008042869A (en) 2005-10-05 2008-02-21 Seiko Epson Corp Electrostatic ultrasonic transducer, ultrasonic speaker, sound signal reproducing method, ultra-directional acoustic system, and display device
WO2008042230A2 (en) 2006-09-28 2008-04-10 Holosonic Research Labs. Inc. Capacitive load driving device
WO2008046175A1 (en) 2006-10-20 2008-04-24 Con-Space Communications Ltd. Throat microphone assembly and communications assembly
WO2008086085A2 (en) 2007-01-03 2008-07-17 Biosecurity Technologies, Inc. Ultrasonic and multimodality assisted hearing
DK2445231T3 (en) 2007-04-11 2013-09-16 Oticon As Hearing aid with binaural communication connection
GB0721162D0 (en) 2007-10-29 2007-12-05 Sonitor Technologies As Patient wrist tag
KR101511575B1 (en) 2007-11-29 2015-04-13 히엔쉬 이노베이션스 비.브이. An electrostatic speaker system
US20110212777A1 (en) 2008-04-17 2011-09-01 Power Digital Communications Co., Ltd. Game device enabling three-dimensional movement
CN101262177A (en) 2008-04-22 2008-09-10 英飞特电子（杭州）有限公司 Current control synchronization commutation driving circuit
US8162840B2 (en) 2008-07-16 2012-04-24 Syneron Medical Ltd High power ultrasound transducer
US20120057734A1 (en) 2008-07-23 2012-03-08 Asius Technologies, Llc Hearing Device System and Method
US8498425B2 (en) 2008-08-13 2013-07-30 Onvocal Inc Wearable headset with self-contained vocal feedback and vocal command
US8106712B2 (en) 2008-12-24 2012-01-31 Georgia Tech Research Corporation Systems and methods for self-mixing adaptive bias circuit for power amplifier
US8009022B2 (en) 2009-05-29 2011-08-30 Microsoft Corporation Systems and methods for immersive interaction with virtual objects
US20110051977A1 (en) 2009-08-28 2011-03-03 Losko David J Ear Canal Microphone
US20110077080A1 (en) 2009-09-30 2011-03-31 Syed Ashraf Meer 3D Gaming client for interactive musical video games inventor(s)
US8565458B2 (en) 2010-03-05 2013-10-22 Audiotoniq, Inc. Media player and adapter for providing audio data to hearing aid
WO2011159724A2 (en) 2010-06-14 2011-12-22 Norris Elwood G Improved parametric signal processing and emitter systems and related methods
US20120029912A1 (en) 2010-07-27 2012-02-02 Voice Muffler Corporation Hands-free Active Noise Canceling Device
US8531123B2 (en) 2010-12-20 2013-09-10 O2Micro, Inc. DC/DC converter with multiple outputs
US8958580B2 (en) 2012-04-18 2015-02-17 Turtle Beach Corporation Parametric transducers and related methods
US8983098B2 (en) 2012-08-14 2015-03-17 Turtle Beach Corporation Substantially planate parametric emitter and associated methods
US8879768B2 (en) 2012-11-14 2014-11-04 Aac Acoustic Technologies (Shenzhen) Co., Ltd. Earpiece having adjustable front vent

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4546391A (en) * 1982-02-04 1985-10-08 Olympus Optical Co., Ltd. Video signal recording apparatus
US4613912A (en) * 1982-09-10 1986-09-23 Hitachi, Ltd. Recording and reproducing apparatus for a video tape recorder
US5539705A (en) * 1994-10-27 1996-07-23 Martin Marietta Energy Systems, Inc. Ultrasonic speech translator and communications system
US20040047477A1 (en) * 2001-07-11 2004-03-11 Bank Jeevan G. Power amplification for parametric loudspeaker
US8849185B2 (en) * 2003-04-15 2014-09-30 Ipventure, Inc. Hybrid audio delivery system and method therefor
US20070127746A1 (en) * 2005-12-07 2007-06-07 Seiko Epson Corporation Drive control method of electrostatic-type ultrasonic transducer, electrostatic-type ultrasonic transducer, ultrasonic speaker using electrostatic-type ultrasonic transducer, audio signal reproducing method, superdirectional acoustic system, and display
US20080137881A1 (en) * 2006-02-07 2008-06-12 Anthony Bongiovi System and method for digital signal processing
US20080152172A1 (en) * 2006-12-20 2008-06-26 Seiko Epson Corporation Electrostatic ultrasonic transducer, and ultrasonic speaker, audio signal reproduction method, ultra-directive sound system, and display apparatus using electrostatic ultrasonic transducer
US20100260362A1 (en) * 2009-04-10 2010-10-14 Sander Wendell B Electronic device and external equipment with configurable audio path circuitry

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140161278A1 (en) * 2011-09-22 2014-06-12 Panasonic Corporation Sound reproduction device
US9565496B2 (en) * 2011-09-22 2017-02-07 Panasonic Intellectual Property Management Co., Ltd. Sound reproduction device
WO2015159037A1 (en) * 2014-04-18 2015-10-22 Akoustic Arts Unidirectional loudspeaker enclosure
FR3020231A1 (en) * 2014-04-18 2015-10-23 Akoustic Arts UNIDIRECTIONAL SOUND SPEAKER
US10129657B2 (en) 2014-04-18 2018-11-13 Akoustic Arts Unidirectional loudspeaker enclosure

Also Published As

Publication number Publication date
WO2013106596A1 (en) 2013-07-18
US9036831B2 (en) 2015-05-19

Similar Documents

Publication Publication Date Title
JP5450820B2 (en) Directional sound system
US8600076B2 (en) Multiband DRC system and method for controlling the same
EP2269301B1 (en) System and method of reducing power consumption for audio playback
US10200000B2 (en) Handheld electronic apparatus, sound producing system and control method of sound producing thereof
CN104811154B (en) The method of Sound producing system and the amplification of its audio
US20150010168A1 (en) Sound producing system and audio amplifying method thereof
EP3240302A1 (en) Handheld electronic apparatus, sound producing system and control method of sound producing thereof
US9036831B2 (en) Amplification system, carrier tracking systems and related methods for use in parametric sound systems
US9456271B2 (en) Method and apparatus for outputting audio signal
JP2012165377A5 (en)
US20070030983A1 (en) High efficiency audio reproduction
US20130322652A1 (en) Method and apparatus for processing audio signal
US9124226B2 (en) Method of outputting audio signal and audio signal output apparatus using the method
JP6817567B2 (en) Digital amplifier
US20160057545A1 (en) Piezoelectric speaker driving system and method thereof
US20130028445A1 (en) Method for processing audio signal and audio signal output apparatus adopting the same
US20080285760A1 (en) Audio system for improving a signal to noise ratio
JP2011211655A (en) High frequency amplifier
US20160173986A1 (en) Ultra-low distortion integrated loudspeaker system
JP2014204229A (en) Amplifier module and signal transmitter
JP2012090164A (en) Av amplifier
JP2007067868A (en) Low-pitched sound amplification digital signal processor
US9473869B2 (en) Audio signal processing device
GB2568223A (en) Bass generator 20Hz&gt; audio system reinforcement
EP2128978B1 (en) Reproducing apparatus and reproducing method

Legal Events

Date Code Title Description
AS Assignment

Owner name: PARAMETRIC SOUND CORPORATION, CALIFORNIA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NORRIS, ELWOOD G.;REEL/FRAME:030269/0612

Effective date: 20130124

AS Assignment

Owner name: BANK OF AMERICA, N.A., AS AGENT, CALIFORNIA

Free format text: MEMORANDUM AND NOTICE OF SECURITY INTEREST IN INTELLECTUAL PROPERTY;ASSIGNOR:PARAMETRIC SOUND CORPORATION;REEL/FRAME:032608/0143

Effective date: 20140331

AS Assignment

Owner name: TURTLE BEACH CORPORATION, CALIFORNIA

Free format text: CHANGE OF NAME;ASSIGNOR:PARAMETRIC SOUND CORPORATION;REEL/FRAME:033887/0437

Effective date: 20140520

STCF Information on status: patent grant

Free format text: PATENTED CASE

AS Assignment

Owner name: CRYSTAL FINANCIAL LLC, AS AGENT, MASSACHUSETTS

Free format text: SECURITY INTEREST;ASSIGNOR:TURTLE BEACH CORPORATION;REEL/FRAME:036159/0952

Effective date: 20150722

AS Assignment

Owner name: BANK OF AMERICA, N.A., AS AGENT, CALIFORNIA

Free format text: SECURITY INTEREST;ASSIGNORS:TURTLE BEACH CORPORATION;VOYETRA TURTLE BEACH, INC.;REEL/FRAME:036189/0326

Effective date: 20150722

AS Assignment

Owner name: CRYSTAL FINANCIAL LLC, AS AGENT, MASSACHUSETTS

Free format text: SECURITY INTEREST;ASSIGNOR:TURTLE BEACH CORPORATION;REEL/FRAME:045573/0722

Effective date: 20180305

AS Assignment

Owner name: BANK OF AMERICA, N.A., AS AGENT, CALIFORNIA

Free format text: SECURITY INTEREST;ASSIGNORS:TURTLE BEACH CORPORATION;VOYETRA TURTLE BEACH, INC.;REEL/FRAME:045776/0648

Effective date: 20180305

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YR, SMALL ENTITY (ORIGINAL EVENT CODE: M2551); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

Year of fee payment: 4

AS Assignment

Owner name: TURTLE BEACH CORPORATION, CALIFORNIA

Free format text: TERMINATION AND RELEASE OF INTELLECTUAL PROPERTY SECURITY AGREEMENTS;ASSIGNOR:CRYSTAL FINANCIAL LLC;REEL/FRAME:048965/0001

Effective date: 20181217

Owner name: TURTLE BEACH CORPORATION, CALIFORNIA

Free format text: TERMINATION AND RELEASE OF INTELLECTUAL PROPERTY SECURITY AGREEMENTS;ASSIGNOR:CRYSTAL FINANCIAL LLC;REEL/FRAME:047954/0007

Effective date: 20181217

FEPP Fee payment procedure

Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

FEPP Fee payment procedure

Free format text: 7.5 YR SURCHARGE - LATE PMT W/IN 6 MO, SMALL ENTITY (ORIGINAL EVENT CODE: M2555); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YR, SMALL ENTITY (ORIGINAL EVENT CODE: M2552); ENTITY STATUS OF PATENT OWNER: SMALL ENTITY

Year of fee payment: 8

AS Assignment

Owner name: BLUE TORCH FINANCE LLC, AS THE COLLATERAL AGENT, NEW YORK

Free format text: SECURITY INTEREST;ASSIGNORS:VOYETRA TURTLE BEACH, INC.;TURTLE BEACH CORPORATION;PERFORMANCE DESIGNED PRODUCTS LLC;REEL/FRAME:066797/0517

Effective date: 20240313